Telegraphy



July 1, 1924. 1,499,646

A. EEELiNG TELEGRAPHY Filed Aug. 244 1921 Fans/ml!" Patented July 1, 1924.

UNITED STATES PATENT OFFICE.

AUGUST EIBELING, OF BERLIN-SCHONEBERG, GERMANY, ASSIGNOR TO SIEMENS & HALSKE AKTIENGESELIJSCHAFT, 0F SIEMENSSTADT, NEAR BERLIN, GERMANY, A

CORPORATION OF GERMANY.

TELEGRAPH.

Serial No. 495,087.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF IARCE 3, 1921, 41 STAT. L, 1313.)

To all whom it may concern:

Be it known that I, AUoUs'r EBELING, a citizen of the German Empire, residing at Berlin-Schoneberg, Germany, have invented certain new and useful Improvements in Telegraphy (for which I have filed applications in Germany September 27, 1918, Ser. No. 49012; Austria, September 10, 1919: Sweden, December 23, 1919, Ser. No. 5809; Norway; December 24, 1919,Ser. No. 18772; Hungary, April 13, 1920, Ser. No. 9741; Denmark, April 15, 1920, Ser. No. 1006; Switzerland, May 12, 1920, Ser. No. 5628; Holland, June 2, 1920, Ser. No. 14988; France, June 8, 1920, Patent No. 516656; England, June 14, 1920, Ser. No. 16066; Czechoslovakia, June 22, 1920, Ser. No. 4607; Italy, June 29. 1920, Ser. No. 291/131; Japan, July 6, 1920, Ser. No. 58481), of which the following is a specification.

My invention refers to the art of telegraphy and more especiall to a method for reducing the inductive effect of telegra hing currents. As is well known to those s illed in the art, the working of telegraph lines causes considerable trouble inadjacent' lines on account of the strong inductive efi'ect produced by the comparatively heavy working currents required. This is particularly the case if the receiving instruments are of a sensitive nature.

In the operation of telephone lines the vicinity of telegraph lines is extremely annoying as a consequence of the disturbing influence of the inductive efl'ect produced by the telegraph lines, whereby in many cases speaking over long lines is rendered impossible. It is of no use to employ, for instance, end-amplifiers in the telephone lines, as the troubles are then intensified in proportion to the amplification of the speaking currents: negative unsatisfactory results have been ob tained also with selective connections for automatically changing over the amplifiers in the telephone systems. on account of the troubles arising from induction. since the changing over may be effected by the induction currents as well as by the speaking currents.

These induction currents arising from telegraph lines, however, do not only produce trouble in adjacent telephone systems, but one adjacent telegraph system will also disturb the other. For instance, the Hughes typeprinting system will often seriously a cot a high speed telegraph working in a neighboring line. A number of methods have been proposed with a view to eliminating this troublesome inductive efl'ect. Among others may be mentioned the method of subdividing the line by repeater arrangements for reducing the working voltage. These repeater arrangements, however, are sulfering flbm the drawback, that they require trained supervision at their points of installation, and in view of the expense entailed such subdivision should not be carried too far. In consequence thereof the working voltage cannot be reduced sufiiciently to eliminate the objectionable inductive efl'ects. Another protective measure consists in the application of grounded screens, surrounding the line; however this manner of proceeding which is applicable only to cables, entails considerable inconvenience and expense and does not really eliminate the trouble. It is an object of my invention to provide simple means for reducing the inductive efl'ect aforesaid to such an extent, that no trouble be produced in the adjacent lines. I attain this end by highly amplifying the telegraphing currents at the end of the line, and correspondingly reducing the working voltage on the transmitter side, so that only weak currents will flow in the line. By means of suitable amplifying devices. such as a cathode tube, it is easily possible to amplify the currents to such an extent as to permit the working voltage of the telegraph system to be reduced sufliciently so as to adjust the sensitiveness of the telegraph line against induction to approximately the same value as that of the adjacent system. Under these conditions the protective arrangements ordinarily employed in practical telephony are as a rule sufiicient to secure working conditions free from trouble. It then becomes possible to apply amplifiers in selective connection as well as end amplifiers directly for use in telephone systems.

In the accom anying drawing I have diagrammatically illustrated how the weakened or subnormal operating currents of the telegraph line may be amplified at the receiving end of the line. In this diagram, L represents the receiving end of the low potential current telegraph line which is connected to the rid G and filament F of a thermionic amp ifier which has its plate P and filament F connected in circuit with the telegra h receiver R, a battery B being inserted in t e late circuit in the conventional manner. he filament F is in the customary way heated by means of a heating battery A.

The application of my invention is of special advantage in connection with multile core cables, the cores of which are workmg in connection with receiving instruments of different sensitiveness, and which are particularly sensitive against the inductive effect. As a matter of course the invention may also be suitably applied to simultaneous sending and receiving systems and to uadruplex working. As is well known to t ose skilled in the art, the latter mode of telegraphing consists in three signaling connections being established over two pairs of lines by short-circuiting the ends of the two pairs of lines by means of alternating current resistances, a third station being connected to the middle of each resistance. which do not constitute impediments of any importance to the working of the third stations. It is therefore possible to have a signaling connection over each pair of lines and simultaneously a further signaling connection over the two lines.

I claim:

1. The method of eliminating disturbing inductive effects of telegraph lines or the like on neighboring lines, which consists in reducing the working current, normally required to operate the receiving instrument, to a value at which its inductive effect on neighboring lines becomes negligible, and in amplifying said subnormal working current at the receiving end of the line to a value suitable to operate the receiving instrument.

2. The method of eliminating disturbing inductive efl'ects of telegraph lines or the like on neighboring lines highly sensitive against induction, which consists in reducing the working current of the telegraph line, normally required to operate the receiving instrument, to a value at which the sensitiveness of the telegraph line against induction becomes substantially e ual to the sensitiveness of the neighboring inc, and in amplifying said subnormal working current at the receiving end of the telegraph line to a value suitable to operate the receiving instrument.

In testimony whereof I allix my signature.

AUGUST EBELING.

DISCLAIMER.

l.499,646.--Augu-wt Ebeling, Berlin-Schoneberg, Germany. TBm-nRAPH'i'. Patent dated July 1, 1924. Disclaimvr filed October 21, 1927, by the assignee, iS'iemcns LC Halake Ailvtiengexellm'hafl.

Hereby enters this disclaimer to that part of the claim in said patent which in the following words, to wit:

1. The method of eliminating dislurhing inductive effects of telegraph lines or the like on neighboring lines, which consists in reducing the. working current, nnrmally required to nporntc the receiving instrument. In a value at which its inductive effect on neighboring lines heroine negligible, and in amplifyin said subnormal working current at the receiving end of the line to a value suits le to operate the receivin instrument.

[Oficzal Gazette November 8, 19957.] 

